Munduruku Indigenous children: health situation in an area with high mercury exposure.

Abstract

Objective: The Munduruku indigenous people are among those most severely impacted by mercury (Hg) contamination in the Amazon region. Mercury exposure can have severe consequences for the physical and cognitive development of children. We aimed to describe the health assessment in indigenous Munduruku children in the Tapajós River basin, possibly exposed chronically to Hg.

Methods: A cross-sectional study with children <12 years old living in the Sawré Muybu (SM), Poxo Muybu (PM), and Sawré Aboy (SA) villages. We collected data between October 29th and November 9th, 2019, through interviews and clinical evaluation (child neurodevelopment tests and anthropometric measurements), and measured blood hemoglobin levels and Hg in hair samples. The history of immunization and other health issues were collected from the Brazilian health booklets. We investigated the prevalence of Hg exposure ≥ 6.0 µg/g. The measure of association used was the Prevalence Ratio (PR), with a 95% CI.

Results: We examined 83 children, 40 in SM, 15 in SA, and 28 in PM. 51.8% were girls, 45.7% had completed the vaccination schedule, 16.0% had changes in the neurodevelopment test, and 13.9% had anemia. Their weight and height/length averages were (Z-scores) -0.86 and -1.59, respectively. 45.1% of children had Hg-levels ≥ 6.0 µg/g. The prevalence of mercury contamination in children in SA was almost four times greater (PR:3.66; 95%CI 2.17-6.18) than that in children in SM, and girls were almost twice as likely (PR:1.67; 95%CI 1.07-2.62) to have mercury levels ≥ 6.0 µg/g, when compared with boys in the study villages.

Conclusions: The higher concentration of hair Hg-levels occurred in SA, where Hg exposure is higher. Although we cannot prove causality, we believe that understanding the possible health impacts of mercury exposure among the Munduruku children is vital for developing strategies to mitigate these effects and for supporting the fight for their rights and the protection of their territories.